The PV solar panels generate electricity by the photovoltaic effect – they produce an electric current when they are exposed to the light. Simply open the 2 panels and expose to direct sunlight to put your solargorilla to work. The technically advanced solid panels ensure superb power and reliable performance, in a tough casing that's ready to travel. The green LED indicates the strength of charge. Performance of Solar Gorilla will very according to levels of sunlight and device being powered.